Device for adding fine particle-sized solids to a liquid stream

ABSTRACT

A device for adding fine particle-sized solids in a continuous casting operation whereby a uniform rate of addition of said solids is achieved by controlling the rate of flow of solids by means of a series of metering orifices in a feed bar attached to the bottom of a hopper and then propelling the particles through a series of tubes or conduits into the molten metal stream.

United States Patent Ronald W, Stout Gary. lnd.;

John R. Albrecht. Grosse Point Park, Mich. 798,634

Feb. 12, 1969 July 13, 1971 Inland Steel Company Chicago, Ill.

lnventors Applv No Filed Patented Assignee DEVICE FOR ADDING FINEPARTICLE-SIZED SOLIDS TO A LIQUID STREAM 4 Claims, 4 Drawing Figs.

US. Cl 222/193, 302/56, 164/57, 266/34 T int. Cl 1B67d 5/54 Field ofSearch 222/193- References Cited UNTTED STATES PATENTS l/l904 Millspaugh222/134 12/1908 Stromborg.... 266/34 X 2/1929 Allen 222/486 X 6/1938Schanz 222/193 2/1956 Kolks 222/195 9/1966 Brown, Jr. et a1 266/34 (T)Primary Examiner-Robert A. Reeves Assistant Examiner-David A. ScherbelAttorneyMerriam, Marshall, Shapiro & Klose ABSTRACT: A device for addingfine particle-sized solids in a continuous casting operation whereby auniform rate of addition of said solids is achieved by controlling therate of flow of solids by means of a series of metering orifices in afeed bar attached to the bottom of a hopper and then propelling theparticles through a series of tubes or conduits into the molten metalstream.

PATENTED Jun BB?! 3592' 363 SHEET 1 OF 3 BY g.. 4.2 1% #2 ATTORNEYSPATENTEUJULI alsn 7 3,592,363

' sum 2 [1F 3 3//\/ 33 32 v I 4f;

k I k I NVENTORS M vac if" ATTORNEYS DEVICE FOR ADDING FINEPARTICLE-SIZED SOLIDS TO A LIQUID STREAM BACKGROUND OF THE INVENTION Thesubject invention relates to the production of alloys and particularlyto a device for adding fine particle-sized solids to a liquid stream asthe molten metal passes from a ladle to a tundish in a continuouscasting operation.

The addition of fine-sized particles to steel has been disclosed byearlier patents. Inasmuch as most additive materials are easily oxidizedat the high temperatures involved with molten steel, it is importantthat the material to be added he quickly and uniformly distributedthroughout the steel and that the mixing operation be completed in asshort a time as possible.

It is also important that the material be uniformly distributed toaccomplish maximum effectiveness with a minimum use of the addedmaterial.

A number of devices have been suggested in the past for supplying leadpellets, metallic aluminum or other solids into a molten metal stream inan attempt to obtain thorough distribution of the material. An exampleof a device for adding aluminum shot is shown in US. Pat. No, 3,224,051to Brown et al. issued Dec. 2 I 1965. Brown et al. includes a gun havinga substantially horizontally positioned barrel through which an airstream flows, and a hopper for containing fine-sized particles mountedatop the barrel.

Brown et al. employs a vertical tube which communicates the bottom ofthe hopper with the gun barrel at a location adjacent to an air-jetnozzle extending into the gun barrel along the axis thereof. The air-jetnozzle is longitudinally adjustable along the axis of the barrel to varythe size of the opening which communicates the bottom of the hopper withthe barrel and thereby controls the rate of flow of solid particles fromthe hopper in the gun barrel. A conduit extends from the barrel at apoint downstream from the vertical tube into the hopper and diverts aportion of the airstream flowing through the barrel into the hopper toagitate the fine-sized solid particles in the hopper. The air streamemanating from the nozzle in the bar rel propels the particles throughthe barrel and into the stream.

The disadvantage of the device shown in Brown et al. is that it isdesigned to place a premeasured, relatively large amount of solidmaterial of a lower density than the melt, into the melt in a shortperiod of time, and is unsuited to furnish continuous and uniform supplyof the solid, fine-sized material as is required when teeming ingots orin continuous casting. This is so because the design of the barrel inBrown et al. permits the backup of aluminum shot at the intersection ofthe barrel and the vertical tube from the hopper. Such a backup, atleast in the case of lead particles, will vary the flow of metal intothe liquid steel and, consequently, have a nonuniform effect on themetal.

In addition, the method required to fill the hopper causes the rate offlow of material to be varied. The air nozzle in the barrel is broughtforward towards the vertical tube from the hopper in order to block offthe flow of material as it is supplied to the hopper. The nozzle mustthen be withdrawn to the desired position which causes solid material tofill the voids in the barrel. When the airflow is commenced, the flow ofmetal is necessarily nonuniform until flow from the hopper and throughthe vertical tube is stabilized.

Where the linear application of fine-sized solids is critical, deviceslike Brown et al. are not suitable.

In addition. and most important, Brown et al. and similar devices in theart employ high quantities of air for propelling the fine-sizedparticles through the gun. For instance. Brown et al. allows the entireamount of airflow to proceed past the vertical tube and past that pointwhere the airflow is broken into a component which proceeds through thebarrel into the stream while some is diverted up into the hopper. Amajor portion of the air introduced into the barrel proceeds to thestream. Where oxidization may be critical, devices using such a largeamount of air are unacceptable.

SUMMARY OF THE INVENTION The present invention is designed to remedythese disadvantages and provide a quick control and uniform supply offine-sized particles. The device made in accordance with this inventionconsists of a gun having a barrel mounted for swiveling on a turretbase. Mounted above the barrel and connected thereto by a conduit andvertical tube is a hopper for containing the fine-sized solid material.The barrel is inclined downwardly from the intersection with the conduitto facilitate the flow of the particles into the stream. An air or inertgas supply is employed primarily for the purpose of freeing the leadparticles in the hopper and vertical tube rather than to propel theparticles. Hereinafter reference will be made to air only for the sakeof brevity. An airhose extends from the air supply source to the hopperwhere it is released through a nozzle located immediately above thevertical tube for agitating the fine-sized particles and drawing theminto and through the vertical tube,

A second air supply and nozzle is located above the barrel andintersects the vertical tube at such an inclination so as to free thevertical tube of clogging and direct the particles into the barrel anddownwardly toward the stream.

A metering bar having various size openings therethrough is disposedbetween the hopper and the barrel and limits the amount of material thatcan pass to the barrel.

With the nozzles so located and with the addition of such a meteringbar, minimum amounts of air are required and a uniform, highlycontrollable rate of flow can be achieved.

The device of the present invention may be used to add lead, otheralloying elements or fluxes.

DESCRIPTION OF THE DRAWINGS Further understanding of the subjectinvention can be had by reference to the drawings wherein:

FIG. 1 is an elevation of the subject invention;

FIG. 2 is a cross-sectional view of the gun used in the subjectinvention;

.FIG. 3 is an elevation of the housing used in the subject invention;and

FIG. 4 is a side view showing the use of the subject inventron.

DETAILED DESCRIPTION Referring first to FIG. 4, the device I0 is shownemitting particles into stream S as the stream travels from ladle L intotundish T. Referring now to FIGS. l-3, wherein common reference numeralswill be used, the device 10 consists of an open topped hopper 11positioned over barrel 14 and connected thereto by a housing 31. Hopper11, barrel l4 and housing 31 are mounted on tripod 12 having a swivelarrangement for directing the flow of particles. Hopper 11 is shown inFIG. 2 partially filled with fine-sized particles which, for the purposeof this discussion, are lead particles in the amount desired to be addedto stream S.

The sides of hopper 1] are tapered inwardly substantially from its opentop to its base 20. Spaced above base 20 is a false bottom 26. In thespace between base 20 and false bottom 26 there exists a channel 15 inwhich there is received a movable metering bar 16 having meteringorifices or openings 28, 28, 28", and 28", said openings 28,28, 28", and28" being of various diameters corresponding to the rate of flow of thematerial desired.

Mounted in the center of hopper 11 above false bottom 26 is an airinjector 40 having a nozzle 42 spaced above aperture 41. Air is suppliedto air injector 40 by means of airhose 18 which extends through agrommet 32 or the like through the side of hopper 11 to air supplysource 17. The vertical distance between nozzle 42 and aperture 41 mustbe great enough to allow the particles in hopper II to be drawn into theaperture 41 by means of gravity and the suction caused by the airpassing from nozzle 42 through aperture 41.

The rate of flow of particles from hopper ll may be varied bymanipulating metering bar 16 in channel 15 so that the desired opening,e.g., 28 is in vertical alignment with aperture 41 and air injector 40.Guide bar 16 is secured in the desired position by means of a ball check24 which is urged into detents 25 on metering bar 16 by means of spring23.

Metering bar withdrawal limit 48 is provided to prevent metering bar 16from accidentally being pulled back too far during operation andcreating a full on" condition.

Base 20 is provided without a cleanout port 27 through which particlesthat are trapped within the space between false bottom 26 and base 20can be removed. Channel E is provided with one or more recesses 30 intowhich particles which may otherwise impede the movement of metering bar16 may fall.

Hopper 11 is mounted above'housing 31 which housing 31 includes avertical bore 29 placed in vertical alignment with air injector 40, aninjector line 32 and conduit 34.

Air injector line 32' includes an airhose 19 which is connected to airsupply source 17 and a nozzle 33 through which air passes into verticalbore 29 at junction 38. Nozzle 33 enters vertical tube 29 at adownwardly directed angle in order to direct the flow of material fromvertical tube 29 into conduit 34 and then to barrel l4.

Barrel 14 is an elongated tubular member having mounted at one end anair supply hose 35 connected to air supply source 17 and at the otherend a nozzle 36. Immediately prior to nozzle 36 are pressure reliefports 21. A shield 47 is provided so that relief ports 21 vent into theencompassing shield 47, thereby creating an air-cooled nozzle 36. Shield47 has the added function ofa splash guard.

Barrel I4 is positioned so that nozzle 36 is lower than the point atwhich conduit 34 intersects barrel 14. A sleeve 46 made of asbestos orother heat resistant material may be provided around barrel 14 tomaintain the temperature of the barrel at an acceptable level.

In actual use, the device is set up and positioned near the point wherethe dry material is to enter the stream with the nozzle 36 of barrel 14at some convenient distance from the stream. With the metering bar 16positioned so that none of the openings 28, 28', 28", and 28" are invertical arrangement with the vertical bore 29 and air injector 40, thehopper which can be of any convenient size is charged with the materialto be added and the propelling pressure set to produce the required rateof flow. Prior to the actual use of the device, the flow rate of thematerial to be added to the stream must be determined experimentally.When the continuous casting is to be started and the stream begins toflow, metering bar 16 is moved from the closed position to thepreselected open position. The flow rate is controlled by thecombination ofthe selected meter orifices in the guide bar and thepressure of the propellant. Additions of the material to be fed are madeto the hopper either manually or mechanically as required. By varyingthe diameter and internal shape of nozzle 36 of barrel 14 and/or byvarying the size and number of the relief ports 21. the shape of thedelivery stream can be regulated.

In the manufacture of lead bearing steels, it is desired to add from 4to l2 lbs. per steel ton of very fine mesh lead shot, usually finer than20 mesh (ASTM), to the stream of molten metal as the stream flows fromthe ladle to the tundish. This amount oflead shot must be addeduniformly while and whenever steel flows from the ladle to the tundish,necessitating a rapid opening and shutting off of the lead stream.

In actual operation, steady line air pressure of 80200 p.s.i. isemployed and the diameters of the meter orifices 28. 28. 28". and 28" inmetering bar 16 are established in view of the type and size of thematerial to be used. Where it is desired to add lead particles, it issuggested that there be three meter orifices with diameters of at least0.500, 0.375 and 0.312

inches.

In the subject invention, the air supply to the barrel 14 is normallyclosed and is only used to clear barrel 14 of particles when required.It is not used to propel the particles. The air supply to airhose 18 andair nozzle 42 is regulated from 0 to p.s.i., as required, with theopening in the nozzle 42 being 0.060 inches. The gap between nozzle 42and aperture 41 is 0.150 inches. Airhose 18 is a 5/32-inch [.D. plastictubing in rigid copper conduit.

Air injector line 32' is -inch diameter smooth bore and the orifice innozzle 33 is 0.020 inch. Air is supplied at steady line pressure.

Air injector line 32' and nozzle 33 intersects the r-onch diametersmooth bore vertical tube at approximately a 45angle. The particles thatare motivated by air from nozzle 33 are propelled into conduit 34 andinto barrel 14 which is positioned at an angle approximately 1 1 5 fromthe vertical bore 29 and extending downwardly toward nozzle 36. Barrel14 is approximately l inch l.D., 9 feet long and of stainless steel.

The entire device is mounted on a tripod base with a 360- ball bearingturntable. Appropriate thumb screws or the like can be used to securethe device on the turntable or to facilitate altering the direction ofthe flow of material from the device.

The above discussion was made for purposes of illustration only and isnot intended as a limitation of the invention. It is understood thatothers working in the art can make various alterations in theabove-described specific embodiment while remaining within the scope ofthe invention.

We claim:

1. In a device for adding fine particle-sized solids to a molten metalstream in a continuous casting operation, said device having a hopperwith an opening in the bottom wall thereof, said solids being adapted tobe stored in said hopper prior to being added to said stream, a barrellocated under said hopper through which said solids are adapted to bedirected into the stream;

an improvement in said device, said improvement comprisconnecting meansfor connecting said hopperto said barrel,

said connecting means comprising:

a first conduit having two ends, one of said first conduit endsterminating close to said hopper opening;

said first conduit being positioned in substantially vertical alignmentwith said opening;

a second conduit having two ends and inclined to said first conduit, oneof said second conduit ends terminating as the remaining end of saidfirst conduit and the remaining end of said second conduit terminatingat said barrel;

said barrel being inclined downwardly from said connecting means to thefree end of said barrel;

restrictive means for controlling the passage of solids through saidopening, said restrictive means comprising:

metering means having a plurality of orifices of varying sizes, saidmetering means located below said hopper opening and contiguous to saidhopper end of said first conduit, said metering means having means forselectively placing and maintaining one of said orifices insubstantially vertical alignment with said opening in said hopper;

a first fluid injector means located in said hopper, said first injectormeans having a nozzle positioned adjacent said opening, with saidopening in said nozzle being substantially smaller in size than the sizeof said bottom wall opening;

a second fluid injector means located adjacent an opening in saidconnecting means; and,

said second fluid injector means having a nozzle means inclined at anacute angle to said connecting means and in a direction away from saidhopper.

2. The improvement described in claim 1 wherein said second conduit isin substantial axial alignment with said second fluid injector means.

3. The improvement described in claim 1 comprising:

said barrel communicates with said second conduit and is inclineddownwardly towards said stream;

tering means comprises a metering bar located between said bottom walland said connecting means, said bar having a plurality of orifices ofvarying sizes located therein and said bar having selector meansattached thereto for selectively moving said bar relative to saidopening in said wall to position and maintain one of said orifices insubstantial alignment with said opening.

1. In a device for adding fine particle-sized solids to a molten metalstream in a continuous casting operation, said device having a hopperwith an opening in the bottom wall thereof, said solids being adapted tobe stored in said hopper prior to being added to said stream, a barrellocated under said hopper through which said solids are adapted to bedirected into the stream; an improvement in said device, saidimprovement comprising; connecting means for connecting said hopper tosaid barrel, said connecting means comprising: a first conduit havingtwo ends, one of said first conduit ends terminating close to saidhopper opening; said first conduit being positioned in substantiallyvertical alignment with said opening; a second conduit having two endsand inclined to said first conduit, one of said second conduit endsterminating as the remaining end of said first conduit and the remainingend of said second conduit terminating at said barrel; said barrel beinginclined downwardly from said connecting means to the free end of saidbarrel; restrictive means for controlling the passage of soLids throughsaid opening, said restrictive means comprising: metering means having aplurality of orifices of varying sizes, said metering means locatedbelow said hopper opening and contiguous to said hopper end of saidfirst conduit, said metering means having means for selectively placingand maintaining one of said orifices in substantially vertical alignmentwith said opening in said hopper; a first fluid injector means locatedin said hopper, said first injector means having a nozzle positionedadjacent said opening, with said opening in said nozzle beingsubstantially smaller in size than the size of said bottom wall opening;a second fluid injector means located adjacent an opening in saidconnecting means; and, said second fluid injector means having a nozzlemeans inclined at an acute angle to said connecting means and in adirection away from said hopper.
 2. The improvement described in claim 1wherein said second conduit is in substantial axial alignment with saidsecond fluid injector means.
 3. The improvement described in claim 1comprising: said barrel communicates with said second conduit and isinclined downwardly towards said stream; a nozzle located at the streamend of said barrel, said nozzle being provided with a plurality ofpressure relief ports spaced circumferentially about said nozzle; ashield positioned over said nozzle and defining a space therebetween sothat air escaping from said relief ports may serve to cool said nozzle;and, a sleeve to encompass the major portion of said remaining portionof said barrel and of a heat resistant material.
 4. The improvementdescribed in claim 1 wherein said metering means comprises a meteringbar located between said bottom wall and said connecting means, said barhaving a plurality of orifices of varying sizes located therein and saidbar having selector means attached thereto for selectively moving saidbar relative to said opening in said wall to position and maintain oneof said orifices in substantial alignment with said opening.